JPH0139898Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention uses a dual carburetor, and connects the intake path from the dual carburetor to the combustion chamber to the primary side of the dual carburetor. a primary intake path from the carburetor;
This invention relates to an intake device that is separated into two paths, a secondary side intake path from a secondary side carburetor.

[Conventional technology and its problems]

In order to improve ignition and combustibility in the low-load, low-speed range of an internal combustion engine, and to improve output in the high-load, high-speed range, the intake air from the dual carburetor to the combustion chamber of each cylinder is Separating the route into two routes, the primary intake route from the primary carburetor and the secondary intake route from the secondary carburetor in a dual carburetor, is a prior art practice. Showa 54-
91514, and this prior art document further describes a secondary side intake passage from the primary side carburetor to the primary side intake port to the combustion chamber in the dual type carburetor, and It is described that the secondary side intake passage from the secondary side carburetor to the secondary side intake port to the combustion chamber in the combustion chamber is arranged in two stacked upper and lower stages at the connection to the carburetor.

However, in this prior art, the primary side intake passage and the secondary side intake passage have a circular cross-sectional shape over their entire length, similar to the primary side and secondary side intake ports that have circular cross-sections with respect to the combustion chamber. , the cross-sectional area of both intake passages at the connection to the carburetor is:
Since the cross-sectional area of both intake passages must be larger than the area at which they connect to the intake port, arranging the connections between both intake passages and the carburetor in two layers makes it difficult to connect both intake passages to the carburetor. The height of the entire connecting portion of the intake passage becomes higher than the sum of the diameter of the primary intake passage and the diameter of the secondary intake passage.

Therefore, the mounting position of the vaporizer will be higher,
The overall height of the engine including the carburetor increases as the carburetor is mounted at a higher position, resulting in an enlarged engine.

Moreover, in this prior art, the primary intake passage and the secondary intake passage have a circular cross-sectional shape over their entire length, similar to the primary and secondary intake ports that have circular cross-sections with respect to the combustion chamber. Therefore, the miscibility of fuel and air in the primary intake passage and the secondary intake passage was low, and the flow resistance in the primary intake passage and the secondary intake passage was large.

The object of the present invention is to solve the problem when the connection portions of both intake passages to the carburetor are arranged in two layers, one above the other.

[Means for solving problems]

In order to achieve this objective, the present invention has developed a system for each cylinder in a multi-cylinder internal combustion engine using a dual carburetor.
A primary side intake port and a secondary side intake port are formed, each having an intake valve, and each of the primary side intake ports is connected to the primary side carburetor in the dual carburetor through a primary side intake passage. The next side intake ports are each communicated with the second side carburetor in the dual carburetor through the second side intake passage, and the connection part of the first side intake passage to the carburetor and the second side In an internal combustion engine in which a connection portion of an intake passage to a carburetor is arranged in two layers, upper and lower, an opening of each primary side intake port and each secondary side intake port to a side surface of the internal combustion engine, The cross-sectional shape of the connection part to the carburetor in the primary side intake passage and the connection part to the carburetor in the secondary side intake passage are arranged in a horizontal line in a circular cross section, and the height dimension of each is It is formed into a flat rectangular shape with a dimension smaller than the diameter at the intake port and a width dimension larger than the diameter at each intake port, and from the connection part to the carburetor in the primary intake passage and the secondary intake passage to the The section leading to the connection to the intake port is formed so as to change from the flat rectangular cross section to a circular cross section, and furthermore, the primary side intake passage is formed substantially horizontally in side view, while the secondary side The intake passage is configured to be inclined diagonally downward toward the secondary intake port when viewed from the side.

[Effect]

With this configuration, the area of the cross section at the connection part of both the primary and secondary intake passages to the carburetor is increased by increasing the width dimension of the rectangular cross section at the connection part. The height of the connection of each intake passage to the carburetor can be made arbitrarily larger than the area of the cross section at the connection to the intake port. Since it can be made lower by making it larger than the cross-sectional area of , and by making the air flow resistance smaller, the height of the entire connecting part, which is the combined height of both intake passages, is lower than that of the prior art. It will be lower than that.

In this case, by arranging the primary side intake passage to be substantially horizontal when viewed from the side, the carburetor can be installed at a lower height.

Moreover, by forming both the primary and secondary intake passages so that their cross-section changes from a flat rectangular to a circular cross-section, the change in cross-sectional shape promotes the mixing of the air and fuel flowing inside them. It is possible to do so.

Furthermore, the openings of the primary intake port and secondary intake port of each cylinder toward the side of the internal combustion engine are arranged horizontally in a line, while the secondary intake passage faces diagonally downward toward the secondary intake port. By adopting the configuration that is inclined to the side, the bending angle from the secondary side carburetor to the secondary side intake passage is an obtuse angle that is larger than a right angle, so the air flow resistance in the secondary side path is reduced, and the This makes it possible to improve air filling efficiency in the load/high rotation range.

[Effect of idea]

Therefore, according to the present invention, the height dimension of the connection part to the carburetor in both the primary and secondary intake passages can be reduced without increasing the flow resistance in both the primary and secondary intake passages. On the other hand, since the height of the carburetor can be lowered, the overall height of the internal combustion engine is reduced by the connection between the primary intake passage to the carburetor and the secondary intake passage. By stacking the connection parts to the engine in two stages, it is possible to avoid the increase in the number of parts, and it is possible to reduce the size of the internal combustion engine.

In both the primary and secondary intake passages,
Since the mixing properties of air and fuel can be promoted, the combustion of the mixer in each cylinder can be significantly improved, and the acceleration response of the internal combustion engine can be improved.

Since the air filling efficiency in the high load/high rotation range can be improved, the output of the internal combustion engine in the high load/high rotation range can be significantly improved.

It has the effect of

〔Example〕

Hereinafter, an embodiment of the present invention will be explained with reference to the drawings.
2, A3, A4 in-line 4-cylinder internal combustion engine,
Reference numeral 2 denotes an intake manifold joined to the side surface of the internal combustion engine 1 with a joining flange 2a.
2 shows a double carburetor attached to the intake manifold 2, and each cylinder in the internal combustion engine 1 has a primary intake port 4 with a circular cross section, a secondary intake port 5 with a circular cross section, and an exhaust port. Each of the intake ports 4 and 5 is provided with an intake valve 7 and 8, respectively, and in this case, the internal combustion engine 1 is The openings to the side surfaces are arranged in a horizontal line, and the ignition of the internal combustion engine 1 is normally A1-A3-A4-A2 or A1-A2.
-A4-A3 order.

The dual carburetor 3 includes a primary carburetor 9 and a secondary carburetor 10, as is conventionally known, and the throttle valve 12 in the secondary carburetor 10 is the throttle valve 12 in the primary carburetor 9. From when the valve 11 is fully open or close to fully open, the throttle valve 1
1, and this dual carburetor 3 has a secondary side carburetor 10 located close to the internal combustion engine 1, and a primary side carburetor 9 located closer to the internal combustion engine 1. They are arranged so that they are located at distant locations.

The intake manifold 2 includes a primary side collection part 13 that communicates with the primary side carburetor 9 of the dual carburetor 3, and a secondary side collection that communicates with the secondary carburetor 10 of the dual carburetor 3. 14, and the intake manifold 2 has two directions, one from the primary side gathering part 13 to the first cylinder A1 and the second cylinder A2, and the other from the third cylinder A3 and the fourth cylinder A4. Two primary side intake passages 1 extending in two directions
5 and 16, and the secondary side gathering part 14
a direction from to the first cylinder A1 and the second cylinder A2,
Two primary side intake passages 17, 18 extending in two directions: toward the third cylinder A3 and the fourth cylinder A4
It is equipped with

The ends of both primary side intake passages 15 and 16 in the intake manifold 2 are connected to each cylinder A1, A2, and A.
3, A4 branches into twig intake passages 19, 20 and 21, 22 to the primary intake port 4 in a tournament shape, and both secondary intake passages 17,
The tip of 18 is the twig intake passage 2 to the secondary side intake port 5 in each cylinder A1, A2, A3, A4.
They are branched into 3 and 24 and 25 and 26 in a tournament shape. In this case, both secondary side intake passages 1
The pair of twig intake passages 23, 24 and 25, 26 which branch out in a tournament shape at 7 and 18 are the pair of twig intake passages 1 which branch out in a tournament shape at both primary side intake passages 15, 16, respectively.
9, 20 and 21, 22.

In a side view of the engine 1, both the primary side intake passages 15 and 16 are oriented substantially horizontally, and the connecting portions of the both secondary side intake passages 17 and 18 to the secondary side gathering part 14 are Located on the upper surface of the connecting portion of the passages 15, 16 to the primary gathering portion 13, both the secondary intake passages 17, 18 are configured to be inclined diagonally downward with respect to the internal combustion engine 1 when viewed from the side. .

On the other hand, the cross-sectional shapes of the connecting portions of both the primary side intake passages 15 and 16 to the primary side gathering portion 13 and the connecting portions of both the secondary side intake passages 17 and 18 to the secondary side gathering portion 14 are Both primary side intake passages 15, 16 are formed into a flat rectangular shape with a diameter smaller than the diameter of each intake port 4, 5 and a width larger than the diameter of each intake port 4, 5. and a flange 2a for connecting the internal combustion engine 1 from the connecting portions of the secondary side intake passages 17, 18 to the collecting portions 13, 14.
The portion leading to the cross section is formed so that the cross section changes from the flat rectangular cross section to a circular cross section.

Note that a chamber 27 for preheating intake air, which includes an inlet 28 and an outlet 29 of cooling water for the internal combustion engine 1, is formed on the lower surface of the primary side gathering portion 13 and both the primary side intake passages 15, 16.

In this configuration, in a low load/low rotation range where only the throttle valve 11 of the primary side carburetor 9 in the dual carburetor 3 is open, the air-fuel mixture from the primary side carburetor 9 flows through both the primary side intake passages 15, A pair of twig intake passages 19, 20, 21, 22 which pass through 16 and branch into tournament shapes at their tips.
When the throttle valve 12 in the secondary carburetor 10 opens in conjunction with the throttle valve 11, the throttle valve 12 in the secondary carburetor 10 opens in conjunction with the throttle valve 11. In addition to the air-fuel mixture from the primary carburetor 9 being sucked into the combustion chamber of the cylinder, the air-fuel mixture from the secondary carburetor 10 is also sucked into both secondary intake passages 1.
A pair of twig intake passages 23 and 2 which pass through 7 and 18 and branch into a tournament shape at their tips.
It is inhaled from 4, 25, and 26.

In addition, although the above-mentioned embodiment showed the case where it was applied to a 4-cylinder internal combustion engine, the present invention is not limited to a 4-cylinder internal combustion engine, but can also be applied to other multi-cylinder engines such as a 3-cylinder engine or a 6-cylinder engine. Needless to say.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a plan view of an internal combustion engine, FIG. 2 is a cross-sectional view taken from the side of FIG. 1,
Figure 3 is a cross-sectional view of Figure 1, and Figure 4 is a cross-sectional view of Figure 1.
FIG. 2 is an enlarged cross-sectional view of the figure. 1... Internal combustion engine, 3... Dual carburetor, 4...
Primary side intake port, 5...Secondary side intake port,
6, 7...Intake valve, 9...Primary side carburetor, 10...
...Secondary side carburetor, 15, 16...Primary side intake passage, 17,18...Secondary side intake passage.

Claims (1)

[Scope of utility model registration request] Each cylinder in a multi-cylinder internal combustion engine using a dual carburetor is formed with a primary intake port and a secondary intake port each equipped with an intake valve, and each primary intake port is connected to a primary intake passage. communicates each secondary side intake port with the primary side carburetor of the dual type carburetor through the secondary side carburetor through the secondary side intake passage, and the In an internal combustion engine in which a connecting portion of the primary side intake passage to the carburetor and a connecting portion of the secondary side intake passage to the carburetor are stacked in two layers, each of the primary side intake ports The openings of each secondary side intake port to the side of the internal combustion engine are arranged horizontally in a circular cross section, while the connection part to the carburetor in the primary side intake passage and the connection part to the carburetor in the secondary side intake passage are arranged horizontally in a circular cross section. The cross-sectional shape of the connection part to the device is formed into a flat rectangular shape with a height smaller than the diameter of each intake port and a width larger than the diameter of each intake port, and the primary side A portion of the intake passage and the secondary intake passage from the connection part to the carburetor to the connection part to the intake port is formed so as to change from the flat rectangular cross section to a circular cross section, and further, the primary side intake passage An intake system for an internal combustion engine, wherein the secondary intake passage is formed to be substantially horizontal when viewed from the side, and the secondary intake passage is inclined obliquely downward toward the secondary intake port when viewed from the side.